Ski boot



R. STOHR SKI BOOT Jan. 16, 1968 Filed June 13, 1966 INVENTOR Ru? S+ol1r BY 4 nTrom'vs s United States Patent 3,363,342 SKI BOOT Rudolf Stiihr, Tuttiingen, Germany, assiguor to Rieker & Co., Tuttlingen, Germany Filed June 13, 1966, Ser. No. 557,006 Claims priority, application Germany, Dec. 30, 1965, R 42,342 3 Claims. (Cl. 36-25) ABSTRACT OF THE DISCLOSURE A ski boot having a sole whose ball part, i.e., the part disposed below the region normally occupied by the ball of the wearers foot, has a lower Shore hardness than the remainder of the sole, e.g., the ball part has a Shore hardness of between about 65 and 75 and the remainder of the sole has a Shore hardness of at least about 85. As a result, the toe and heel parts of the sole are suficiently hard to take up the pressure to which they are subjected by the ski binding, while the ski boot as a whole does not unduly restrain the rolling motion of the foot on the ski.

The present invention relates to a ski boot with an outer sole of rubber or plastic which is cast upon the upper and preferably directly upon the same. The outer sole of the known ski boots has a relatively high Shore hardness which usually amounts to more than 85. This was regarded as necessary in order to insure that the sole would take up the pressure to which the toe and heel parts of the sole are subjected by the ski binding.

Although a ski boot which is provided with a cast-on sole has considerable advantages over a ski boot on which the sole is sewed or glued, it has always been regarded as a disadvantage that the cast-on sole restrains the rol ing motion of the foot on the ski which reduces the efficiency and performance of the skier during long-distance runs. It also did not appear possible to make a cast-on rubber or plastic sole of a greater softness or a lower Shore hardness since this would reduce the resistance of the toe and heel parts of the sole so much that the boot would no longer hold properly within the ski binding.

It is an object of the present invention to provide a ski boot with a cast-on outer sole which complies with both requirements as indicated above, and it is therefore a feature of the invention to provide a cast-on sole in which the ball area, which is disposed below the ball of the wearers foot, has a considerably lower Shore hardness than the other parts.

According to the invention, the area of the sole of the ski boot which is affected by the rolling motion of the foot is therefore made of such a softness, for example, of about 70 Shore, that it will permit the foot to carry out such a rolling motion along the ski without any restraint, and this soft area is designed so as not to affect the pressure resistance of the sole at the toe and heel areas thereof. The area of the outer sole which according to the invention is made of a softer degree is generally made of a length of 8 to 10 cm., as seen in the longitudinal direction of the sole.

In the production of a ski boo-t according to the invention it is possible to vulcanize softer and harder parts of the outer sole upon the upper in a single operation. The vulcanizing mold is then charged with several blanks of Patented Jan. 16, 1968 different grades of rubber or plastic which, when the vulcanizing process is completed, will result in an outer sole of the desired Shore hardness. These blanks are arranged in the mold in accordance with the position of the different sole parts of different degrees of hardness as desired in the finished sole. Experience has shown that the different grades of rubber or plastic will not flow into and combine with each other to such an extent as to prevent the individual areas of the outer sole from attaining the desired gradation in hardness in accordance with the invention. An excessive coalescing of the individual grades of rubber or plastic may also be prevented by making the individual blanks of rubber or plastic mixtures which differ from each other distinctly insofar as the temperature is concerned which is required for their vulcanization and cure.

For injecting the material for the outer sole upon the upper, it is advisable to employ a multistage injection method, for example, one consisting of two stages, in which the areas which are to be filled out in the mold during the first injection stage are blocked off from the area which is to be filled out during the second injection stage.

The accompanying drawing illustrates a ski boot with a cast-on outer sole in which the different areas of this sole as previously described should have diiferent degrees of Shore hardness.

In this drawing, the outer sole 2 of rubber or plastic is cast upon the upper 1 of a ski boot and is provided at the toe and heel areas with projecting bulges 3 which are drawn upwardly for a certain distance along the outer side of the upper. The softer part of the outer sole, shown at S, lies within the area of the rolling motion of the foot, there being harder parts H ahead of and behind this softer part. While, as aforesaid, the softer part of the sole will have a Shore hardness of about 70, this value may, in practice, lie within the range of about 65 and Shore, while the harder parts of the sole will be at least about Shore and may, in practice lie within the range of about 88-95 Shore. These numerical values, it will be understood are not strictly limitative but serve to exemplify the considerably lower Shore hardness of the ball part as compared to the Shore hardness of the remainder of the sole, as stated throughout the instant specification and claims.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. A ski boo-t having an upper and an outer sole made of rubber or plastic and cast on said upper, said sole having a ball part which is spaced from the front and rear of the boot and front and rear parts constituting the remainder of said sole, said ball part being d sposed below the region to be occupied by the ball of the wearers foot and having a Shore hardness of between about 65 and 75 and the remainder of said sole having a Shore hardness of at least about 85.

2. A ski boot as defined in claim 1 wherein said ball part has a Shore hardness of about 70.

References Cited UNITED STATES PATENTS 2,374,487 4/ 1945 Jayne 3632 2,768,598 3/1956 Inga 3632 3,05 0,874 8/ 1962 Silombra 362.5

4 1/1966 Ludwig 362.S 6/ 1940 Sewall 3628 9/1950 La Chapelle 3628 9/1966 Reinert et a1. 3628 X FOREIGN PATENTS 11/1961 Germany.

PATRICK D. LAWSON, Primary Examiner. 

